In recent years, granular activated carbon produced from coal as the raw material has become used as the carbon material for removing sulfur from discharge gas from thermoelectric power plants, chemical plants, metal refineries, and others.
And, the de-sulfurizing operations of discharge gas with the activated carbon is classified into the so-called dry method and wet method. In either method, since adsorption and reproduction are repeatedly done over a long period of time, the activated carbon is required to have, along with its adsorptibility, various mechanical strength such as impact resistance strength, wear-resistance strength, and so forth.
In case, however, coal is used as the raw material, it is a general trend that, when the absorptibility is increased, the mechanical strength decreases, and, on the contrary, when the mechanical strength is to be increased, the adsorptibility is lost. Therefore, emergence of the carbon material for de-sulfurization excellent in its adsorptibility and mechanical strength has heretofore been desired.
Furthermore, the carbonization treatment of shaped raw material coal is done by heating the raw material to the ultimate temperature of approximately 600.degree. to 1,000.degree. C. using a heating furnace such as rotary kiln, fluidized bed, mobile bed, etc.. However, this treatment has shortcomings such that, depending on the manner of handling the raw material for the carbonization treatment, the shaped coal is subjected to crush and wear to cause poor rate of yield, and, further, the mechanical strength of the resulting carbon material is lowered because of such crush and wear. Such shortcomings are particularly remarkable when the rotary kiln is used as the heating furnace.